Study On Urban Network In Northwest China From The Perspective Of Flow Space

With the rapid development of Globalization,the influence of geographical distance on social development has been gradually weakened.The flow of commodities,personnel,capital,technology and other elements is more convenient and efficient.The theory of "flow space" came into being in this context.The spatial organization form of various elements has changed to the network mode of multi center,flattening and mobility.All kinds of transportation infrastructure and information network have broken through the traditional barriers between cities and promoted the formation of regional urban network.The focus of the researchers is also shifted from the horizontal comparison of urban scale,function type and regional space,to the analysis of urban network mode,characteristics and strength of connection.This paper chooses prefecture level cities in Northwest China as research units.From the perspective of urban flow space,the traffic flow and information flow between nodes of northwest city network are characterized by common train,high-speed train,highway car and Baidu search index.By giving weight to the spatial elements of each flow,this paper constructs a composite urban network in Northwest China from the perspective of multiple traffic information flow,and explores the spatial distribution,agglomeration characteristics,and hierarchical structure of the urban network in Northwest China by using GIS spatial analysis method.Then using the social network analysis method,the structural characteristics and organizational model of the northwest urban network were analyzed from the aspects of flow direction,density,centrality,and agglomeration.The purpose of this paper is to deepen the indicative significance and regional cognition of urban network analysis from the perspective of multiple traffic information flow.The main conclusions are as follows:Based on the perspective of traffic flow,northwest urban network has significant spatial differences and hierarchical characteristics,and the main line of spatial connection basically coincides with the main traffic lines.The traffic network based on normal speed trains presents a pattern of "one horizontal and three vertical",and has significant spatial dependence.Most of the eastern regions,including Xi'an,Lanzhou,Urumqi and its surrounding areas,have obvious agglomerative characteristics.The traffic connection of high-speed railway has formed a spatial pattern "one axis and two cores",which is formed with Xi'an and Lanzhou as the core and Longhai passenger dedicated line as the main axis.The traffic connection of high-speed railway has obvious polarization phenomenon and spatial difference characteristics.The spatial agglomeration type is mainly high-level and low-level areas,and the bipolar agglomeration phenomenon is more obvious.The overall level of the information flow network is relatively high and the development is relatively balanced.In the spatial pattern,it takes the provincial capital city as the core and radiates and spreads to the surrounding areas in a circle way.Each province forms a relatively complete information network based on its geographical location,population,urban economic and cultural industry development status.The spatial agglomeration of information network is generally fragmentary.Different types of agglomeration in the East are cross distributed,and the west is relatively single.A small number of core cities have more network attraction.The main stream of the northwest composite city network is based on the regional proximity,with the relative matching of comprehensive strength,and presents the spatial pattern of "two centers and multiple hubs".The loosely connected urban flow is generally the expansion of some remote cities in Xinjiang and Qinghai to cities with the middle comprehensive strength.The comprehensive network perfection is in the middle,the network density from the provincial perspective is significantly different,and the inter provincial network density is relatively small as a whole.The degree centrality and the middle centrality show the obvious polarization phenomenon.The high value areas gather in the Lanxin Baolan traffic corridor and the Longhai Lanxin line respectively.Some areas of Ningxia and Qinghai have formed the low value continuous area.The big cities have the absolute advantage.The "Matthew effect" of the northwest urban network is significant.The characteristics of regional internal clusters are obvious,and the distribution of agglomerated subgroups has a certain degree of organization.Based on the proximity of geographical distance,a relatively stable four area pattern has been formed,and closely connected regions gather in space.